1/* A Fibonacci heap datatype.
2   Copyright 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
3   Contributed by Daniel Berlin (dan@cgsoftware.com).
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it
8under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 2, or (at your option)
10any later version.
11
12GCC is distributed in the hope that it will be useful, but
13WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING.  If not, write to
19the Free Software Foundation, 51 Franklin Street - Fifth Floor,
20Boston, MA 02110-1301, USA.  */
21
22/* Fibonacci heaps are somewhat complex, but, there's an article in
23   DDJ that explains them pretty well:
24
25   http://www.ddj.com/articles/1997/9701/9701o/9701o.htm?topic=algoritms
26
27   Introduction to algorithms by Corman and Rivest also goes over them.
28
29   The original paper that introduced them is "Fibonacci heaps and their
30   uses in improved network optimization algorithms" by Tarjan and
31   Fredman (JACM 34(3), July 1987).
32
33   Amortized and real worst case time for operations:
34
35   ExtractMin: O(lg n) amortized. O(n) worst case.
36   DecreaseKey: O(1) amortized.  O(lg n) worst case.
37   Insert: O(2) amortized. O(1) actual.
38   Union: O(1) amortized. O(1) actual.  */
39
40#ifndef _FIBHEAP_H_
41#define _FIBHEAP_H_
42
43#include "ansidecl.h"
44
45typedef long fibheapkey_t;
46
47typedef struct fibheap
48{
49  size_t nodes;
50  struct fibnode *min;
51  struct fibnode *root;
52} *fibheap_t;
53
54typedef struct fibnode
55{
56  struct fibnode *parent;
57  struct fibnode *child;
58  struct fibnode *left;
59  struct fibnode *right;
60  fibheapkey_t key;
61  void *data;
62#if defined (__GNUC__) && (!defined (SIZEOF_INT) || SIZEOF_INT < 4)
63  __extension__ unsigned long int degree : 31;
64  __extension__ unsigned long int mark : 1;
65#else
66  unsigned int degree : 31;
67  unsigned int mark : 1;
68#endif
69} *fibnode_t;
70
71extern fibheap_t fibheap_new (void);
72extern fibnode_t fibheap_insert (fibheap_t, fibheapkey_t, void *);
73extern int fibheap_empty (fibheap_t);
74extern fibheapkey_t fibheap_min_key (fibheap_t);
75extern fibheapkey_t fibheap_replace_key (fibheap_t, fibnode_t,
76                                         fibheapkey_t);
77extern void *fibheap_replace_key_data (fibheap_t, fibnode_t,
78                                       fibheapkey_t, void *);
79extern void *fibheap_extract_min (fibheap_t);
80extern void *fibheap_min (fibheap_t);
81extern void *fibheap_replace_data (fibheap_t, fibnode_t, void *);
82extern void *fibheap_delete_node (fibheap_t, fibnode_t);
83extern void fibheap_delete (fibheap_t);
84extern fibheap_t fibheap_union (fibheap_t, fibheap_t);
85
86#endif /* _FIBHEAP_H_ */
87